Operating mechanism for disconnect switches



Aug. 4, 1964 J. A. TURGEON 3,143,608

OPERATING MECHANISM FOR DISCONNECT SWITCHES Filed Dec. 30, 1960 5 Sheets-Sheet l l-Bl L INVENTOR.

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QPERATING MECHANISM FOR DISCONNECT SWITCHES Filed Dec. 50, 1960 5 Sheets-Sheet 5 A r rpz frr United States Patent 3,143,698 OPERATING MECHANISM FDR DISCONNECT SWITCHES .loseph A. Tnrgeon, Toronto, Ontario, Canada, assignor to Eastern Power Devices Limited, Port Credit, Ontario,

Canada, a limited-liability company of Canada Filed Dec. 30, 1960, Ser. No. 79,889 8 Claims. (Cl. 20tl48) This invention relates to switching devices, and has particular reference to an improved blade operating mechanism for large disconnect switches which have dual motion.

Large dual motion disconnect switches are conventionally designed to carry large currents at large voltages e.g., 2,000 amperes and kv. These switches conventionally include an insulator-mounted contact jaw having two spaced contact members, and a disconnect blade which is pivotally mounted by a hinged bearing on an insulator to swing into the contact jaw and thus make electrical contact with the contact members. The blade is also rotatable about its longitudinal axis within the hinged bearing so that the blade may be slipped, edgefirst, between the contact members of the jaw and then be rotated about its axis so that the edges meet the jaw members. The blade is thus securely wedged and gripped within the jaw. A trunnion projects from the blade and hingedly carries a connector rod from a hinge pin which is offset from the blade. A manually or automatically operated crank is journaled for horizontal rotary movement from a location which is in line with the blade and is hinged to the connector rod by a crank pin. During rotation of the crank past the blade centerline, the crank serves to laterally shift the connector rod and the end of the trunnion to cause rotary movement of the blade around its longitudinal axis, whereby the blade may be disengaged from the contact members of the jaw. When the crank pin follows the portion of its rotary path which is substantially in the direction of the blade axis, the trunnion is pulled toward its pivot and the blade swings upwardly out of the jaw. Reversal of the crank rotation results first in the swinging of the blade downwardly into the jaw and then in the rotation of the blade to wedge it in the contact jaw. Contact and disconnect is thus produced by reversal of rotation of the crank.

As the crank pin moves past the longitudinal centerline of the blade in its circular path, the trunnion hinge pin is rotated along the circumference of a circular path whose plane is perpendicular to the longitudinal axis of the blade. The connector rod to which the hinge pin is connected thus tends to move in a substantially straight path transverse to the blade axis as the crank pin moves past the blade axis. Accordingly, unless some compensating means is provided, the circular path of the crank will cause the blade to dip into the jaw during rotary movement of the blade about its axis.

It is an object of this invention to provide a disconnect switch having a novel blade operating mechanism which will maintain the axial orientation of the blade while it is rotated in the jaw during the connecting or disconnection action of the blade.

It is generally an object of this invention to provide a new and improved blade crank operating mechanism for dual motion disconnect switches.

It is another object of the invention to provide a disconnect switch operating mechanism which will satisfactorily turn and lift the blade and which has a movement that corresponds to the path followed by the blade-controlling trunnion connector rod.

Yet another object of the invention is to provide a. guiding mechanism for the blade of a disconnect switch which will guide the trunnion connector rod pin along a straight ice line and then along a curved path in one smooth stroke resulting from a single driving torque applied to a single member.

A further object of the invention is to provide an improved disconnect switch which will reduce the operating friction inherent in present devices and obviate the need for compensating means which are designed to prevent blade dip into the contact jaw.

In accordance with the invention the blade of a disconnect switch is rotated within the contact jaw, as well as pivoted relative to the contact jaw, by imparting to the connecting rod, which hinges upon the blade trunnion, movement which follows a substantially linear path transverse to the rod axis and continues in an arcuate path. The liner movement results in smooth turning of the blade about its axis and the arcuate movement swings the blade. The movement described may be accomplished by a straight-line motion device or a straight-line mechanism which is a combination of links arranged to impart rectilinear motion over a limited distance to a rod independent of guides or way. A straight-line motion device may be responsive to the turning of an individual crank and its path may include an arcuate portion.

For a clearer understanding of the invention, its other objects and advantages, reference may be made to the following detailed description and accompanying drawings wherein a preferred embodiment of the invention is illustrated.

In the drawings:

FIGURE 1 is a side elevation of a vertical disconnect switch according to the prior art;

FIGURE 2 is an end view of FIGURE 1;

FIGURE 3 is a plan view of a portion of a vertical disconnect switch according to the prior art wherein the conventional compensating means for the switch mechanism are shown;

FIGURE 4 is an elevation of FIGURE 3;

FIGURE 5 is a plan view of a blade operating mechanism which embodies the principles of this invention;

FIGURE 5a is a view taken in the direction of 5A5A of FIGURE 5;

FIGURE 5b is a view taken in the direction of SB-SB of FIGURE 5;

FIGURE 6 is a side elevation of FIGURE 5;

FIGURE 7 is an elevation of another blade crank operating mechanism which embodies the principles of this invention;

FIGURE 8 is a plan view of FIGURE 7; and

FIGURES 9 through 11 illustrate successive operative positions of the members of the blade crank operating mechanism of FIGURES 7 and 8.

Referring to FIGURES 1 and 2, a conventional vertical disconnect switch of prior art structure is illustrated for the purpose of showing the environmental conditions within which the invention operates. The switch is shown in its closed position and includes three insulators 12, 14 and 16 which stand in a row. This type of switch is shown and described in US. Patent 2,673,902, issued March 30, 1954, to Gustave E. Heberlein, entitled Disconnect Switc A disconnect blade generally designated 20 includes disconnect arm 18 which securely holds a widened beavertail end 19 and is articulated with the top of the insulator 14 for vertical swinging motion by means of a hinged bearing 22. The hinged bearing 22 includes roller bearings (not shown) to allow rotation of the blade 20 about its longitudinal axis. In the position shown the arm 18 has been swung to its lower, i.e., horizontal, position where the end 19 of blade 20 enters a contact jaw 24 which is secured to the top of insulator 16, and includes a pair of contact members 25. As shown, the blade has been rotated upon its horizontal axis to a fiat horizontal position to be wedged in the jaw lifts the blade.

'means of a pin 32, to the end of the forked rod 28 and U is secured for rotation on'its vertical axis to the insulator 12. The insulator 12 is rotatable by means designated 34 to rotate the crank 30 about its vertical axis (which intersects the blade axis) to move' the pin 32 past the axis of blade 20. The trunnion 26 thus rotates the blade 20 about'its axis out of wedged engagement with the contact members 24. Further rotation of crank 30 and consequent movement'of the pin 32 (out of the sheet as shown -in FIGURE 1 and to the left'as shown in FIGURE 2) pulls the trunnion toward the hinged bearing 22 to lift the blade 20 out of the jaw 24, past the angular position 36 shown in phantom lines, to a vertical position above the pivot 22. V a

The difiiculty in this prior art structure is diagrammatically illustrated in FIGURES 3 and 4, wherein a partial plan view of FIGURE 1 is shown. The crank pin 32 is shown connected to the connector rod 28, and having swung in a circular path from an initial position A, past the blade axis position B, to position C to rotate the blade about its axis. Further rotation of the crank The path through which the pin 32 of the rod 28 can travel is however defined by the line 40. Accordingly, some means are usually used to compensate for the distance designated 42 which constitutes the height of the segment bounded by the chord'and the arc of the I circle between positions A and C.

Conventional switches utilize aslot 33, in the crank 30 about the pin 32, to compensate for distance 42. This has the disadvantage that it permits backlash on long switch blades and objectionable bounce when the blades reach the open (vertical) position. This has been found to be prevalent even with the slot spring loaded.

Some switches provide no compensation at all. The blade 20 is allowed to move downwardly from the horizontal position and dip lower into the contact jaw with its end 19. This is possible only on small switches because on long blades a stop is required in the jaw.

Other switches, such as shown in FIGURE 4, provide a trunnion 26 which is secured tothe arm 18, both of which are axially and rotatably slidable relative to a hinged support member 44. A cam slot 46 and a pin 48 control the axial movement of the arm 18, blade 20 and trunnion 26. It is not convenient to mount the arm 18 upon support member 44 with ball or roller bearings due to the longitudinal movement of the blade. The bearing sleeve action of the trunnion 26 upon the member 44 results in undesirable high sliding friction.

'The invention essentially replaces the crank 30 with a straight line mechanism so that the crank pin 32 travels along a straight line from position A to C rather than in the path defined by the are from positions A, B, and C. The straight line mechanism then continues from position C to define an are which draws the blade 20 upwardly out of the jaw 24. a 7 Referring to FIGURES 5, 5a, 5b and 6, the blade operating mechanism of the invention is shown in detail as embodied in the 'prior art switch illustrated in FIG- URES 1 and 2. The forked connector rod 28, hingedly connected to the trunnion 26 carries a hinge 48 to allow vertical swinging motion of the rod 28. A trunnion guide link 50is swingably connected at one end to the hinge 48, for horizontal movement, by a vertical hinge pin 51. A curved drive crank 52 is pivotally connected to the link 50, for horizontal movement, by means of a pin 54 in a collar 56. The drive crank 52 is mountedfor horizontal rotation with the insulator 12, upon which it is secured, so that the pin 54 travels clockwise 170 from the jaw into gripping engagement.

position shown in FIGURE 5. An idler crank 58 is pivotally mounted on a shaft 60, ofiset from the axis of crank 52, for rotary horizontal movement and is hingedly secured to a pivot 62 between'the hinge 5i and the pin 54. The idler crank 58 serves to control the relative position of the hinge pin 51 as the drivecrank 52 swings the pin 54 in a circular path. The path traversed by hinge pin 51 first follows a straight line to rotate the blade 20 in the jaw 24 and then follows a substantially arcuate horizontal path which draws the hinge of the trunnion 26 toward the insulator 12 to lift the arm 18 and the blade 20. Reversal of the direction of rotation of the drive crank 52 first causes lowering of the blade 20 into the jaw 24 and then causes turning of the'blade end 19 within the This is accomplished in a smooth, continuous action as a result of a single rotary driving torque. A

In anotherembodiment of the invention the drive crank '52,idle'r crank 58 and the link 50 are arranged as shown iirFIGURES 7-11. The remainder of the switch is as shown in FIGURES l and 2. The cranks 52, 58 and link '50 proceed from an initial position shown in FIGURES 7 and -8 and pass through successive stages, shown in FIG- URES 9-ll due to the rotation ofthe drive crank 52. The phantom lines in FIGURES 81l show the locus of the hinge pin 51. It will be noted that this is also a straight line transverse to the blade axis which turns the blade 20, followed by an are which lifts the blade out of the jaw 24.

Elimination of the axial reciprocating action found in prior art structures of the hinge pin 51 upon the blade 20 and trunnion 24, permits simple conventional ball bearings or roller bearings to be utilized. This results in confining the friction of moving parts to roller or ball bearings and to pins of small radius on the cranks and links. The required operating effort is thus greatly reduced. The eifect of this important advantage increases withthe size of'the disconnect switch relative to their required operating power.

It should be understood, of course, that the foregoing disclosure relates only to preferred embodiments of the invention and that it is intended to cover all changes and modifications of the examples described which do not constitute departures from the spirit and scope of the invention as set forth in the appended claims.

Iclaim: V

l. A disconnect switch comprising stationary contact means, movable contact means including a pivot mount spaced from said stationary contact means and an elongated contact member pivotally mounted in said pivot mount for swinging into electrical engagement with said stationary contact means, said contact member being axially rotatable with respect to said stationary contact means for turning into gripping engagement with said stationary contact means, control means secured to said contact member and hinged to said contact member about an axis at an angle to said contact member for rotating said contact member into and out of gripping engagement with said stationary contact means, said control means including a connector lug located remote from said contact member; and driving means pivotally connected to said connector lug for imparting to said connector lug linear movement transverse to the axis of said contact member whereby said contact member is rotated, and movement in an arcuate path leading away from said stationary contact means whereby said contact member is swung out of electrical engagement with said stationary contact means; said driving means including a straight line mechanism having a link swingably secured at one end to said connector lug, a drive crank pivotally mounted at one location and hinged to said link at one point thereof, and an idler crank pivotally mounted at another location and hinged to said link at another point.

2. A switch as in claim 1 wherein said control means include a trunnion secured to said contact member, a

hinge pin on said trunnion ofiset from said contact member and a connector rod mounted on said hinge pin, said connector lug being mounted at the end of said connector rod.

3. A disconnect switch as in claim 1 wherein said drive crank is hinged to said link at the other end thereof and said idler crank is hinged to said link intermediate the ends of the link.

4. A disconnect switch as in claim 1 wherein said idler crank is hinged to said link at the other end thereof and said drive crank is hinged to said link intermediate the ends of the link.

5. A blade operating mechanism for a disconnect switch; said disconnect switch comprising an extending blade, a pivotal support for pivotally receiving a first portion of said blade, and a contact jaw for receiving a second portion of said blade; said blade being rotatable about its own axis and being rotatable about said pivotal support; said blade operating mechanism including a connector rod and a driving means connected to said connector rod; one end of said connector rod being pivotally connected to a connecting portion of said blade located between said first and second portions of said blade; the other end of said connector rod being connected to said driving means; said driving means including a rotatable drive crank and connecting linkage means connected between said drive crank and said other end of said connector rod; said connecting linkage including a single guide link connected to said other end of said connector rod for translating rotation of said drive crank into continuous motion of said one end of said connector rod comprised of an arcuate motion portion followed by a straight line motion portion,

6. A blade operating mechanism for a disconnect switch; said disconnect switch comprising an extending blade, a pivotal support for pivotally receiving a first portion of said blade, and a contact jaw for receiving a second portion of said blade; said blade being rotatable about its own axis and being rotatable about said pivotal support; said blade operating mechanism including a connector rod and a driving means connected to said connector rod; one end of said connector rod being pivotally connected to a connecting portion of said blade located between said first and second portions of said blade; the other end of said connector rod being connected to said driving means; said driving means including a rotatable drive crank and connecting linkage means connected between said drive crank and said other end of said connector rod; said connecting linkage including a single guide link connected to said other end of said connector rod for translating rotation of said drive crank into continuous motion of said one end of said connector rod comprised of an arcuate motion portion follwed by a straight line motion portion; said connecting portion of said blade comprising a trunnion.

7. A blade operating mechanism for a disconnect switch; said disconnect switch comprising an extending blade, a pivotal support for pivotally receiving a first portion of said blade, and a contact jaw for receiving a second portion of said blade; said blade being rotatable about its own axis and being rotatable about said pivotal support; said blade operating mechanism including a connector rod and a driving means connected to said connector rod; one end of said connector rod being pivotally connected to a connecting portion of said blade located between said first and second portions of said blade; the other end of said connector rod being connected to said driving means; said driving means including a rotatable drive crank and connecting linkage means connected between said drive crank and said other end of said connector rod; said connecting linkage including a single guide link connected to said other end of said connector rod for translating rotation of said drive crank into continuous motion of said one end of said connector rod comprised of an arcuate motion portion followed by a straight line motion portion; said first portion of said blade entering and leaving said contact jaw with said blade rotated about its axis and out of a high pressure contact position.

8. A blade operating mechanism for a disconnect switch; said disconnect switch comprising an extending blade, a pivotal support for pivotally receiving a first portion of said blade, and a contact jaw for receiving a second portion of said blade; said blade being rotatable about its own axis and being rotatable about said pivotal support; said blade operating mechanism including a connector rod and a driving means connected to said connector rod; one end of said connector rod being pivotally connected to a connecting portion of said blade located between said first and second portions of said blade; the other end of said connector rod being connected to said driving means; said driving means including a rotatable drive crank and connecting linkage means connected between said drive crank and said other end of said connector rod; said connecting linkage including a single guide link connected to said other end of said connector rod for translating rotation of said drive crank into continuous motion of said one end of said connector rod comprised of an arcuate motion portion follwed by a straight line motion portion; said connecting linkage comprising an idler crank and said single guide link pivotally connected to one another; a first portion of said single guide link being pivotally connected to said one end of connector rod; a second portion of said single guide link being pivotally connected to said drive crank.

References Cited in the file of this patent UNITED STATES PATENTS 2,575,707 Gilliland Nov. 20, 1951 

5. A BLADE OPERATING MECHANISM FOR A DISCONNECT SWITCH; SAID DISCONNECT SWITCH COMPRISING AN EXTENDING BLADE, A PIVOTAL SUPPORT FOR PIVOTALLY RECEIVING A FIRST PORTION OF SAID BLADE, AND A CONTACT JAW FOR RECEIVING A SECOND PORTION OF SAID BLADE; SAID BLADE BEING ROTATABLE ABOUT ITS OWN AXIS AND BEING ROTATABLE ABOUT SAID PIVOTAL SUPPORT; SAID BLADE OPERATING MECHANISM INCLUDING A CONNECTOR ROD AND A DRIVING MEANS CONNECTED TO SAID CONNECTOR ROD; ONE END OF SAID CONNECTOR ROD BEING PIVOTALLY CONNECTED TO A CONNECTING PORTION OF SAID BLADE LOCATED BETWEEN SAID FIRST AND SECOND PORTIONS OF SAID BLADE; THE OTHER END OF SAID CONNECTOR ROD BEING CONNECTED TO SAID DRIVING MEANS; SAID DRIVING MEANS INCLUDING A ROTATABLE DRIVE CRANK AND CONNECTING LINKAGE MEANS CONNECTED BETWEEN SAID DRIVE CRANK AND SAID OTHER END OF SAID CONNECTOR ROD; SAID CONNECTING LINKAGE INCLUDING A SINGLE GUIDE LINK CONNECTED TO SAID OTHER END OF SAID CONNECTOR ROD FOR TRANSLATING ROTATION OF SAID DRIVE CRANK INTO CONTINUOUS MOTION OF SAID ONE END OF SAID CONNECTOR ROD COMPRISED OF AN ARCUATE MOTION PORTION FOLLOWED BY A STRAIGHT LINE MOTION PORTION. 